Total worldwide shipments rose 10.9 percent from the same quarter a year ago to reach 46.1 million during the first quarter, IDC said in a statement Friday.

The research firm said that continued growth in Europe, the Middle East and Asia, as well as in notebook PC shipments, drove the increase, which was about 1 percent higher than IDC's forecast for the quarter. Those regions saw unit shipments rise 15 percent from the same quarter a year ago. The U.S. PC market met IDC's forecast, with growth particularly strong for laptops and in the small- and medium-business sector, IDC said.

Despite the rather upbeat quarterly results, IDC continued to express caution about the second half of the year. The research firm, as well as market research rival Gartner, has said that growth will slow toward the end of this year, resulting in shipment increases of less than 10 percent. Ensuing years could be even tougher, Gartner has said, leading to more intense competition in the market, which has already seen Hewlett-Packard buy Compaq; IBM announce plans to sell its PC business to Lenovo Group, China's top PC company; and Gateway acquire eMachines.

Dell still king of the hill
"It's caution in the sense that we're coming off of higher growth last year and we need to see continued (business) spending" on PCs, said Loren Loverde, director of IDC's Worldwide Quarterly PC Tracker. "So far this quarter is a pretty good sign of that, but the market is maturing and we have forecast slower growth. I would approach (the future) in a measured fashion. I wouldn't be overly optimist or overly conservative."

Dell remained the worldwide PC market's king of the hill during the first quarter. The Round Rock, Texas, PC maker shipped just over 8.7 million PCs, the most in the world, giving it almost 19 percent market share. HP continued in second place, shipping 7.1 million units, and garnered just over 15 percent market share. The two companies grew by 13.6 percent and 10.6 percent, respectively, for the quarter. IBM was a distant third with 2.3 million units. It grew only 2 percent.

Apple Computer had a strong quarter, with unit shipment growth in the 40 percent range. IDC said the Mac Mini helped shipments, while the popular iPod music player likely added a halo effect to the Apple line. The company shipped 1.07 million units worldwide and 565,000 in the